Later this year, Comet ISON will pass through the asteroid belt, enter the Inner Solar System and sidestep Mars on its way past Earth, putting on what scientists expect will be a spectacular heavenly show that is not to be missed.

Astronomers are calling it the “comet of the century.”

Comets offer one of the most spectacular celestial scenes the unaided human eye can see. By November or December, ISON is expected to be brighter than a full moon. Some believe it will be up to 15 times brighter.

While ISON may prove to be brighter than any other comet of the last century, this trip may also be its swan song, as it is projected to end its flight in a fiery death in the sun.

Comets are made of several parts. The core, or nucleus, is a solid snowball of dust and ice. As the comet nears the sun, the nucleus heats up, releasing the mixture of gas, called the coma, and dust, which forms the tail. There is also a plasma ion tail, which can be several hundred million miles long.

Occasionally, a comet is dislodged from its orbit and makes its way toward Earth.

ISON against background stars

Comet ISON, currently in the vicinity of Jupiter, was discovered by two Russian amateur astronomers, Vitali Nevski and Artyom Novichonok, using a 16-inch International Scientific Optical Network telescope in Vitebsk, Belarus. The comet possibly came from the Kuiper Belt, a region of icy small bodies beyond Neptune.

ISON, for the moment, is a faint object, visible only in sophisticated telescopes, but that will change in the next few months.

British astronomer David Whitehouse, in the London Independent, reports that by the end of summer, it will become visible in small telescopes and binoculars.

By October, the comet will pass close to Mars, and it will start to become exciting. The surface of the comet will begin to shift as it nears the sun. As it continues to warm, the surface will crack, releasing small puffs of gas from its core, forming the comet’s tail. Slowly at first, but with increasing energy, the gas and dust will reflect even more of the sun’s light

By autumn, the view should be remarkable.

Astronomers have calculated that the comet will not impact Earth, however, it will pass less than 800,000 miles away from Earth, making it easily visible.

Like the moon, comets do not shine on their own. They reflect only about 4 percent of the sun’s rays, about the same luminescence as a lump of coal. So while the sun’s reflection makes comets look brilliantly white from Earth, they are black on the surface.

Parts of a comet

The comet will begin brightening once it comes within Jupiter’s orbit, as the sun’s heat begins boiling the ice locked within, converting it directly into a gas.

The reaction to ISON is likely to recall the excitement of Comet Hale-Bopp, which sailed past the Earth in 1997, appearing as a static smear in the skies across the Northern Hemisphere.

ISON is also set to outshine “the greatest comet of the last century” – Comet McNaught, which shone brighter than Venus as it passed above the Southern Hemisphere in 1965.

There are reports Comet ISON’s path resembles that of the Great Comet of 1680, which is also called Kirch’s Comet or Newton’s Comet. That comet’s tail was reportedly visible during the day.

Comets are known as “dirty snowballs,” although technically a better definition would be “snowy dirtballs,” as they are generally rocky at the surface, with chemical-laden ice inside.

Comets can also give off a distinctive sound as they interact with the various space probes exploring the universe.

The timing of Comet ISON has set the astronomical world abuzz. The comet will be closest to the Earth during a time when the solar system’s star, the sun, will reach the maximum of its 11-year solar cycle.

While the comet will not impact Earth, the solar activity that will light up the comet will also unleash multiple Coronal Mass Ejections, or CME, that project trillions of tons of radioactive material at millions of miles per hour toward Earth.

If a major CME happens when the flare is facing directly toward Earth, satellites risk severe damage and, in some cases, destruction. In a nightmare scenario, a massive solar blast would initiate a cascading series of failures that could severely hamper daily life in today’s information age. Electrical systems would fail, and anything that depends on them — such as food, fuel and energy supply systems — simply would not work. No refrigerators in grocery stores, no pumps at gas stations, no valves controlling flows in dams.

The threat is serious enough that National Oceanic and Atmospheric Administration scientists are watching these celestial events closely as the sun enters what is called the Solar Max. Government agencies are looking at contingency plans for anything from minor power and communication outages to destruction of global power grids and communications systems.

On September 2, 1859, the largest recorded geomagnetic storm dazzled the pre-electronics era with auroras seen around the world. The white-light solar flare was so bright; folks in the northeastern United States could read newspaper just from the light of the aurora. The telegraph system in use all over Europe and North America failed. Telegraph operators were shocked, and telegraph pylons threw sparks, causing telegraph paper to spontaneously catch fire. And when telegraphers disconnected the batteries powering the lines, aurora-induced electric currents in the wires still allowed messages to be transmitted!

ISON might not be the only spectacular comet visible soon. Another comet, called 2014 L4 (PanSTARRS), was discovered last year, and in March and April it could also be a magnificent object in the evening sky.

Comets and other celestial objects have often been regarded as harbingers of events on Earth.

Mark Twain was born during the 1835 appearance of Halley’s Comet, and he predicted he would “go out with it.” He died April 21, 1910, the day following the comet’s return.

The Star of Bethlehem heralding the birth of Jesus is mentioned in Matthew 2:

Where is he that is born King of the Jews? For we have seen his star in the east, and are come to worship him. (Mt 2:2 KJV)

This celestial event is also thought to be foretold in Numbers 24:17 and Isaiah 60:3. It has historically been explained in three ways: as a major comet; as a planetary conjunction or sequence of conjunctions; or as a supernova.

The first-century Roman historian Josephus, in Book VI, chapter 5 of “The Wars of the Jews,” recorded the arrival of a comet before the fall of Jerusalem in AD 70. Josephus recounts a heavenly “sign” that was ignored by those without eyes or minds to consider it at the time:

Thus were the miserable people (the Jews of Jerusalem) persuaded by these deceivers (false prophets), and such as belied God himself; while they did not attend nor give credit to the signs [of the heavens] that were so evident, and did so plainly foretell their future desolation, but, like men infatuated, without either eyes to see or minds to consider, did not regard the denunciations that God made to them.

“Thus there was a star resembling a sword, which stood over the city, and a comet, that continued a whole year.”

Biblical prophecies of the Last Days also include celestial events:

“And I will show wonders in the heavens and in the earth, blood, and fire, and pillars of smoke. The sun shall be turned into darkness, and the moon into blood, before the great and the terrible day of the LORD come.” (Joel 2:30-31 KJV)

From this passage and from Revelation 6:12-13 comes what is known as the “Blood Moon” prophecy.

Blood moon

Four “blood-red” total lunar eclipses will fall on Passover and Sukkot in 2014 and 2015, the same back-to-back occurrences in 1492, 1948 and 1967.

The Blood Moon theory says the Second Coming of Christ will likely occur in 2014 or 2015 when there will be four consecutive, rare lunar eclipses, or a tetrad. The eclipses will coincide with two major holidays on the Jewish calendar in 2014 and 2015: Passover and the Feast of Tabernacles.

Supporters of this theory believe the Rapture likely will coincide with one of the eclipses.

While the world did not end with the end of the Mayan calendar last year, Comet ISON is considered by some to be another celestial sign of things to come.